I would be interested to know what that rectangular shaped fitting on the underside of the Fu23 lid is for? (see 5 posts down). An operating manual perhaps. I ask because there is a similar fitting on the RHS hull of the Luchs hull which I have never been able to establish the purpose of.

The ones inside lids etc are for one sheet only, typically covered by an acetate sheet. The one in the Luchs probably contained a list of electrical users and the currents they draw, similar to the one found in the Kfz 17. This allows the crew to anticipate how long their battery charge will last and when they need to run the engine or deploy the external generator to recharge the battery....